UNIT –III
NANO MATERIALS
Basic Definitions - Distinction between nanoparticles and bulk materials - size-dependent
properties - Mechanical, Chemical, Optical, Electrical and Magnetic properties – Nanoparticles -
nanoclusters, nanorods, nanotubes and nanowires - Synthesis of nanoparticles - Precipitation
method - Hydrothermal synthesis - Solvothermal synthesis - Sonochemical synthesis - Chemical
vapor deposition – Electrodeposition - biogenic synthesis - Applications of nanomaterials.
3.1 INTRODUCTION
The world of materials is rapidly progressing with new and trendiest technologies, and
obviously novel applications. Nanotechnology is among these modern and sophisticated
technologies, which is creating waves in the modern times. Actually, nano technology includes
the concept of physics and chemistry of materials. It beckons a new field coming to the
limelight. So, nanotechnology is an interesting but emerging field of study, which is under
constant evolution offering a very wide scope of research activity.
Nanoscience
Nanoscience is the study of the phenomena and manipulations of materials at atomic,
molecular and macromolecular scales, where properties differ significantly from those at
larger scales.
Nano chemistry
Nanochemistry is a relatively new branch of chemistry concerned with the unique
properties associated with assemblies of atoms or molecules in nano dimension
(approximately 1 to 100 nm). It also deals with the synthesis, characterization, properties
and applications of these nanomaterials.
Nano-technology
Nano-technology is the design, fabrication, characterization and applications of
materials at nano-level (1-100 nm) and converting them into useful devices.
Why NanoTechnology ?
In the materials world, particularly in ceramics, the trend is always to prepare finer
powder for the ultimate processing and better sintering to achieve dense materials with
dense fine-grained microstructure of the particulates with better and useful properties for
various applications. The fineness can reach up to a molecular level (1 nm – 100 nm), by
special processing techniques. More is the fineness, more is the surface area, which
increases the ‘reactivity’ of the material. So, the densification or consolidation occurs very
well at lower temperature than that of conventional ceramic systems, which is finally ‘cost-
effective’ and also improves the properties of materials like abrasion resistance, corrosion
resistance, mechanical properties, electrical properties, optical properties, magnetic
properties, and a host of other properties for various useful applications in diverse fields.
,3.2. TYPES OF NANOMATERIALS
Nanoparticles
Nanoparticles are the simplest form of structures with the sizes in nm range. In
principle, any collection of atoms bonded together with a structural radius of <100nm can
be considered as a nanoparticle.
Nanomaterials
Nanometre is one billionth of a metre.
1nm = 1x10-9 m
The properties of a bulk material will be different from its nanosized particle.
The unique properties of nanosized particles is mainly due to
The smaller particles having a relatively larger surface area compared with their
volume, making them chemically more reactive.
When this size is below 100nm, quantum effects can change the optical, electronic
or magnetic qualities of materials.
Nanocrystal
Nanocrystal is a material particle having one dimension lesser than 100nm and
composed of atoms in either a single or polycrystalline arrangement.
, Quantum dot
Quantum dot is a nanocrystal made of semiconductor materials.
Polymeric Nanoparticles
Polymeric nanoparticles are prepared from polymers. They are considered as
potential drug delivery devices due to applications in drug targeting to particular organs and
tissues.
Dendrimers
Dendrimers is one kind of polymeric nanoparticles constructed by the successive
addition of layers of branching groups. The properties of dendrimers are dominated by the
functional groups on the molecular surface. It finds its applications as solubilizing agents
imaging agents, sensors, drug delivery, Gene therapy, detecting agents such as a dye
molecule.
3.3. CLASSIFICATION OF NANOMATERIALS
The main classification of nanomaterials is based on the dimensions of their
structural elements.
1. Zero-dimensional (0D) nanomaterials: Nanomaterials having diameter
less than 100nm. Example: Nanoparticles, nanoclusters and nanocrystals.
2. One-dimensional (1D) nanomaterials: Nanomaterials having one dimension in the
nanometer scale. It includes nanofibers, nanorods and nanotubes.
3. Two-dimensional (2D) nanomaterials: Nanomaterials having two dimensions in the
nanometer scale. It includes nanofilms, nanowires, nanolayers and nano coatings.
4. Three-dimensional (3D) nanomaterials: Nanomaterials having three dimensions in
the nanometer scale. It includes powders, fibrous, multilayer and polycrystalline
materials.
NANO MATERIALS
Basic Definitions - Distinction between nanoparticles and bulk materials - size-dependent
properties - Mechanical, Chemical, Optical, Electrical and Magnetic properties – Nanoparticles -
nanoclusters, nanorods, nanotubes and nanowires - Synthesis of nanoparticles - Precipitation
method - Hydrothermal synthesis - Solvothermal synthesis - Sonochemical synthesis - Chemical
vapor deposition – Electrodeposition - biogenic synthesis - Applications of nanomaterials.
3.1 INTRODUCTION
The world of materials is rapidly progressing with new and trendiest technologies, and
obviously novel applications. Nanotechnology is among these modern and sophisticated
technologies, which is creating waves in the modern times. Actually, nano technology includes
the concept of physics and chemistry of materials. It beckons a new field coming to the
limelight. So, nanotechnology is an interesting but emerging field of study, which is under
constant evolution offering a very wide scope of research activity.
Nanoscience
Nanoscience is the study of the phenomena and manipulations of materials at atomic,
molecular and macromolecular scales, where properties differ significantly from those at
larger scales.
Nano chemistry
Nanochemistry is a relatively new branch of chemistry concerned with the unique
properties associated with assemblies of atoms or molecules in nano dimension
(approximately 1 to 100 nm). It also deals with the synthesis, characterization, properties
and applications of these nanomaterials.
Nano-technology
Nano-technology is the design, fabrication, characterization and applications of
materials at nano-level (1-100 nm) and converting them into useful devices.
Why NanoTechnology ?
In the materials world, particularly in ceramics, the trend is always to prepare finer
powder for the ultimate processing and better sintering to achieve dense materials with
dense fine-grained microstructure of the particulates with better and useful properties for
various applications. The fineness can reach up to a molecular level (1 nm – 100 nm), by
special processing techniques. More is the fineness, more is the surface area, which
increases the ‘reactivity’ of the material. So, the densification or consolidation occurs very
well at lower temperature than that of conventional ceramic systems, which is finally ‘cost-
effective’ and also improves the properties of materials like abrasion resistance, corrosion
resistance, mechanical properties, electrical properties, optical properties, magnetic
properties, and a host of other properties for various useful applications in diverse fields.
,3.2. TYPES OF NANOMATERIALS
Nanoparticles
Nanoparticles are the simplest form of structures with the sizes in nm range. In
principle, any collection of atoms bonded together with a structural radius of <100nm can
be considered as a nanoparticle.
Nanomaterials
Nanometre is one billionth of a metre.
1nm = 1x10-9 m
The properties of a bulk material will be different from its nanosized particle.
The unique properties of nanosized particles is mainly due to
The smaller particles having a relatively larger surface area compared with their
volume, making them chemically more reactive.
When this size is below 100nm, quantum effects can change the optical, electronic
or magnetic qualities of materials.
Nanocrystal
Nanocrystal is a material particle having one dimension lesser than 100nm and
composed of atoms in either a single or polycrystalline arrangement.
, Quantum dot
Quantum dot is a nanocrystal made of semiconductor materials.
Polymeric Nanoparticles
Polymeric nanoparticles are prepared from polymers. They are considered as
potential drug delivery devices due to applications in drug targeting to particular organs and
tissues.
Dendrimers
Dendrimers is one kind of polymeric nanoparticles constructed by the successive
addition of layers of branching groups. The properties of dendrimers are dominated by the
functional groups on the molecular surface. It finds its applications as solubilizing agents
imaging agents, sensors, drug delivery, Gene therapy, detecting agents such as a dye
molecule.
3.3. CLASSIFICATION OF NANOMATERIALS
The main classification of nanomaterials is based on the dimensions of their
structural elements.
1. Zero-dimensional (0D) nanomaterials: Nanomaterials having diameter
less than 100nm. Example: Nanoparticles, nanoclusters and nanocrystals.
2. One-dimensional (1D) nanomaterials: Nanomaterials having one dimension in the
nanometer scale. It includes nanofibers, nanorods and nanotubes.
3. Two-dimensional (2D) nanomaterials: Nanomaterials having two dimensions in the
nanometer scale. It includes nanofilms, nanowires, nanolayers and nano coatings.
4. Three-dimensional (3D) nanomaterials: Nanomaterials having three dimensions in
the nanometer scale. It includes powders, fibrous, multilayer and polycrystalline
materials.
